SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '248cea6b6507b714804c4a00478b88678ce1cbb34996c12ebb31da2872c8d56f' 
  AND token = 'Mx/CJ0GqVQPPfjlMnGsVOlRS+/TD6HiMkt1kApolQ7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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