SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '05ba04a6faf7b98dbb69184c9701522905905fefa9c4dee5486aa3bc355c07b6' 
  AND token = 'MPYuBgKjrlh88qzhLUDJp3HyJikn2LeM3Xpma0sjo+s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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