SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5758f76739608976694d8ae0fa2d480dac63539215f2f8f9f290d38d4d57ac41' 
  AND token = 'BQ5WfcsLkGijgApZEn1FMSMsK+JWkXy8nnEw2tuBdpk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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