SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b6b467ffe32dc6405e502589d4777835f90cadf7866082fc42ba885760ba255' 
  AND token = 'ge2SQwEC4gJAJsHyegwBUKSu9GSbBhA8foPhfnP4Agw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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