SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '09f96795e02af18fe203905a4cb1eb0134a239c6467179a02460d85b3f924703' 
  AND token = 'lxle7pJz7qtPgUEsWa8enX5nBwk84GUKBKDP+s2L3z8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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