SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'cd6fe76a2900d51d192c959aa602ed787cd391d22bc806de5fbad1df273dda9e' 
  AND token = 'OhPFrGKNXwa7IsBFmMxn7pBxymnudUK1S+KjvG2afo8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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