SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c5adf0267380ce09ce0e3cd7a2443babdec2b9da8a0690e0231a8215ae2aa2b' 
  AND token = '4SVnzSjsqnBSEgR/OLJT4YNRZ9B5iaYWiQFdpvghLzQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}