SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3bc55eb2e86dd85bee9b4cceba025c7cb529c7f745287840359933a31eabdba' 
  AND token = 'xYDTfhLnm8XCtIOokXuaTsX+KiCiWuTLI1AI1F0St3o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}