SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fb993bf33d60215457a2f283ef0de52ce73779410529fdbe585242bf38d2715' 
  AND token = 'greHUI0w8JchzRF3K+L+LtK4PdXGSSNSgtd2waPTlBI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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