SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92fcc1d325559f2fda5f745afbc32f56ba6678981555fc47f7ee7d2dffee0686' 
  AND token = 'P0MCOsF6WpcmsZHwBSalQ+jDRJUs7unGFC0zCZGgxro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00143

JSON explain

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