SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ff28ea407747573f9bb62b407f81e8fd71ebf65ecf3f6a34a1c8cb0fd7ec5e39' 
  AND token = 'GvZZhCE7pz99rcJDI+dgOt1nPMCpHWJng4jXwUhR0iM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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