SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eacfd943acfcf2d4c0a0b683802e84a9df2b6ee78793802b69d443d5e73ec3a9' 
  AND token = 'm7pBhzcjANFRaJh4KXjzhDZCQyD09yh5fvLGpHg8vgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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