SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '206b15b8021538706092341dfb0148cde1b99008cfa819c1181310fdebe5065f' 
  AND token = 'rI4ZicXdhR6EyATtSH+Y8WLUBKQA3Vf8M4ihN+OpapU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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