SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f790d7e2f74d3eff647bc517bba81780af93752c7b0e452be5efcaf7bc0b62b' 
  AND token = 'spGXgMcDiMDTSgVB4jFJQj0XqdZhlxsOGKsKPRgJuj0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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