SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50cbcf606848cf62d2f311433c9fce8bf56f9abf540a299fca6874f583b32e3c' 
  AND token = 'NEHHweHeXoby6yDFV7/7dl/RQ8ebUaEcEHay19uO7Gw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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