SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c03e44682fcd0f2fecf7533d38dacf9d1c9aae1e7a0f4d062719b0b537b1736' 
  AND token = 'cAGcdFzz9nksUiLTCzin50owRlCuMcz4wylCNSXpF38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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