SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ce2b40d1bb6d58492d5d1952e297da43bf141cc62dd681ac03338800295ca00' 
  AND token = 'vx3aZTgniVWvectWNGcNkUapzVgrEHIM2QwhN3gMi1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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