SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70f45921846089062ca2fd76cba14d4337b96fce036ed1bf5fd946b54cf2bd44' 
  AND token = 'zVBamqXVuLpHCH/slAroPB+kCpTDMYnpidSYIefyEnc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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