SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aec5115c7ecfab992f407a0c2de5b231f93a3048467cf9937afb8c14fd387f69' 
  AND token = 'HOG/MLYe+N2dNuIRDitO4Fq/NVRSi/5lTBdws0tFCfQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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