SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de2ffe4d1b09b66eabc8f599144f11491dd648508427f871940db14770a0ba48' 
  AND token = 'aLfz+/p5O2Ks7mFndZnEAnfoWtaRcPsvsLDJL7gXqQI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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