SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3260fada501aba401c368f6336afd403d292ade9a3beeeb88e5ec9e91b42895b' 
  AND token = 'A450y/3QssbXL4udzfqzbFW1izJWexC+pQEphwT34OE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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