SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9bb731eac9c16c158cead5f0cf045eb33d27ae85bf6eb2f3a0b636a097f5bad' 
  AND token = 'HgCNGqLqaP05RSH/EVLNNdoQynPLtwkUyaOCNOxMdjs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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