SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6c7af245c4b589b4383d400038bdbaec3126b91df538264240c850cd58ce39d' 
  AND token = 'S8/j0RjFr7mgf1b5bGKzOOkEXgl0rIIVYhZpQSlRnOc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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