SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aebbc9e4b27b10c8a975df759a663451a846e7a59656a02e3f69824f3f4f8da8' 
  AND token = '8aKQfmJ2U79YEJEESqfsnaJ932fk1332wEgAXILcNDU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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