SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '714f3ccc203f90dca91f49a9130856bd5333ab65ece653084e47426a693a3cf9' 
  AND token = 'h9ESWQHHd0iKwpI+Iabhn8PLyPAse5oVNeBf7OVvUNs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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