SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '940b8a9112ebb32d888ecaa162bcc8b968b84ef1c4645d326f564854077f0916' 
  AND token = 'ob3YYHtr6ulmLPTOPQLH3LD6t9xsrCXCq635gBLOvlY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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