SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3975989bd89b237292e438b0e615e24b061fc301c27ecb005d0eb6ea45346bb' 
  AND token = 'AcCIRPzweibvrbqTt4vE6KIDg+JUepbquE25HcjnywA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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