SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '872e3617fbffdb64e62278f5c1c0c5c128afef1afaec4c8082939c15ac8d0285' 
  AND token = 'hwHKudc1Dakrz570eB33ZjyPyj2haumaVUHvmEB3WwQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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