SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '699883d763f03384b7ae7fcd163a0d398d4831701dc1ba3aea8ffa1d62b6cb50' 
  AND token = '8R4MKbVjzDg7asRuQiI0jwqF/G+xJyV9cUpc+KbztUA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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