SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df8d7962041752347b53e05df5abe7c0bc577662a2dbdc70169c28c8818f523d' 
  AND token = 'AD8yjEMFSHJBZ7CFbOrVPKPgU4ZMRe4Py6zKccfMCqI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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