SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f3c48272cec8a985047260304f4118ace62cc884bcf44dd51ca596957982cfb' 
  AND token = 'mFspQwMyyxOl9jLCZRp9tyB1AzOWEOigl0Lajiw93Gs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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