SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ce2ead472d95b7af5cf3162cc97aab97f4859bcf1746c4977952283def96051' 
  AND token = 'BWlLKpHCVQw+ye7UqIX6KR3+lBWIBsVAeGdhAaQMIIM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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