SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70a933d72c5660ed15742fd92ae9cbad2f792aa1eb8164926098501e64ee3458' 
  AND token = 'IDlPuQBN8JfTmE1aXpi4UBQEM+j3PPUzSF7LPhin6Nk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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