SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '185da827bd5dc81f7ea1d58091423ba8f04d84d7fd24be778bf6359830867f82' 
  AND token = 'fuCzmpNFPzSn5Ikq5Cc4T4YdhnF+I9HEq2kgNnxg3F0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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