SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8afaadee7061f30e7277cd0a93823a450aabca05a3a09b2e365dd3420d7c4b2' 
  AND token = 'QquUGij/cmG+dAakSwvYtJXsRpJudiM6y9POouG2bhE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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