SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e4f622f5a7bdf678efdd5dacdd365952813623d68246f598aa2c9b32447d2c8' 
  AND token = 'TYXN3SMTGCFavuD9/f5uahbkl8sx3UsUSCO+vuYmPCA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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