SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c254c70192eb58225fd6ace674ed68ba7725a763eff960dc01634dcdd4a22e0f' 
  AND token = 'llaj51wt6NEgJ0X/NMwp/39SeDTt8Aw0neYcpJ9kOcw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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