SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '918998067d6fd2ccd9d0b89c7d53ea22ab2f432e556f58dee9b59fe59012257c' 
  AND token = 'UK42cDmMJ3I+2+lmcGvVJC1lMIki5Tpp3OttASm/j8A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}