SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5378226d77432f6612bb9d7029b8ae40f29b41b544afce028b54fbf9665a2047' 
  AND token = 'yJU6UVeVSqwVNmEoHHpZrCVqMHebPYhUqbp+cd7f6gc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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