SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b2067a3b89b7f9b745010a3c920fb8ffe5f5309bc026d98be7a0dc9d51523d5' 
  AND token = 'dumCstE3QCk7ly3M9eWZ/tDR3mNCpoCu1BN9lUBLHHc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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