SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd213c2c98646e12df00a2b5d19dc1e2e3210240af802cc6d75ff34146bb73e3' 
  AND token = 'gcWBfEH2XXBSa4HI775wNRD9VeUzi3UPMI4dMW58JCE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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