SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8931a9c1f6e836fa5f3f0fcf86fc76e3845e80f7d3ca59c31f3620526f883c9e' 
  AND token = 'EJq6Nuea6/jybgPzWy8Tnm4AiPfPwCqB72kJPf8nhs0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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