SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12e80aaf0fee5a243ac226e83c5d644b9ac53b562b16d3596af223c2755100e6' 
  AND token = 'gH4LEZGxH9WljhqI5SpJpMcOrEZvUdDRjJXrvdgA6yw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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