SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d6994ec953fe5abeb148dbfb00d0727c9135eb5c5ac3817689d377cd98840fe' 
  AND token = '0MZU15neKT7qfw6gfb91Qb9L9oTAVkXhuT26n/Do0UA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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