SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99166dcad965ca1ef4341107587c9659197557be2bf6069ed29d26729977f4b0' 
  AND token = 'f3nxqnKCGOpdCxjjucvOmdd3ThxGgLHldA5Nq+hoFUc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}