SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7e44401749892ea440ff9022bbbacb31645585c65c56ddebf0510aafef00bd0' 
  AND token = 'YK97fzdbRpx/alfUUywW1GrzetYtzQcxAVUiwjpev1U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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