SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '00d1211a2e318307b06ecda61d14266e14102cf4728364ca45503758a2b5a147' 
  AND token = 'vFrQ9UPxSc3pcLEIgT5kwOZMztU1AuJlGqyKdxEPw4w=' 
  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"
    }
  }
}