SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77bd7f31507e714671b1f938f43e9a38ccdb297929c1917ee74578bea44048a9' 
  AND token = 'I/aWqM31Wq2Zp9t/ftop8U0VFcbS8Wq5+UshgV7a9Qk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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