SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e38d1db461b4bc234861f46d3db679877956029e5b9404cdf762921d4af68b1' 
  AND token = '/bFR+EIgcl+G+crawRJVZ2rUNKbIv/mC4g1Dzy+vLzI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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