SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '55313b482470e2102da050139217dcc53322d2576857c64ccbf87c0a07846cf2' 
  AND token = 'aBW4Rj4uAt3dvmCUI4ztfTqqV+rhKIh8NNH5d3Qxl7g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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