SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66d1ae055b0936da1104ffe847f028b03a08df1c359b4ddef9d968bf9a8a4959' 
  AND token = 'CehTW0zRbbaWa81p4z8MLlSvN9XiuQQchqll8coxY4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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