SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7af4d4b1c41f2946227559a12918c20b22097789882ef8a562f29f673de89dcc' 
  AND token = 'PdFEcoQU1dQsZYkfSm4Fid5VCHEY45UF48MYzCuCrMs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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