SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1f95b261e0655b9af0820603eae8f0e92ecb114c5b940d69c06176a2f936541' 
  AND token = 'O2MYnd4n6QPukGyYA59pGityKvw7dXoqHn9BuMWpeEc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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