SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c7bde80930cd33cdf929b9163de75aa9f119c5f879afe6961d988adc04c313d' 
  AND token = 'FsbXQISoJHcQCCTALIcAi1ZjcC7Rtz4upor+hQiWQuw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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