SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e3ef5cf1ca2fefcb8dac02c142bc8804b2c13fa0a1b4bd32793d070da9fc45d' 
  AND token = 'pi4DPZCCoznDqzYnHRsZl2gzJkLZBO/EIK92jus2kBI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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