SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f20d6de623e2ae594c44be00f0e6ceaeb37340b5e24f31dfc9980d5da859aae6' 
  AND token = 'C2lVZxsDgnpvOZfh9/FozSPFPpQhRuo9PpPcb+vCfX8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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