SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77f57ac789d53fe7a95bb5a5ed8ef51c53592e38e307c166394be5ff1d973b2d' 
  AND token = 'hCuakKyQv+tCSz/vR8wlJDe1WgPPBVcl0skVjHAIgyc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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