SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '242c741c5b85f37d33717e6ba1706ca6f5606041653aababcda8a6408ec28017' 
  AND token = 'NT+Ab/pilUrHPXbTngrWu4oTxhCPDocRt8NrDx0C7OM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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