SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c27f6906743741f8d14b04afd6d758c32fa0ce2cadcf5482ac84025b47890eb' 
  AND token = 'S8NnM4GdbSEWbaXP0fTGowIGg+br1bgqBUsshhvJqd8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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