SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bea6ef528a80a29aa1e9ed13609a140e5ae0687e033bc95225af55870a1abf0' 
  AND token = 'Uc3OVlCOfwVozl9L4QB9CqQ3K0AVGqkUGrdr1/eFqkE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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