SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e750722394732b1042f3de48cd47a22964a75767784ce183b0fb158f97fb7d4a' 
  AND token = 'GrlYZoGbNY/4qUwcFOzSo2o+nnAwajXGV5+Uz+i1Zjo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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