SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2f3addc01af0ccf34588e86e87bd1a984e954214b1bb70afc43858748cf7776' 
  AND token = 'HS7WzasNwcdT2Kwva+FQ8NVd56q6IKEPESJJ3Vlu/Mk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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